1. Field of the Invention
This invention relates to heat recuperating apparatus for radiant tube burners.
2. Prior Art
A radiant tube burner assembly is comprised of a fuel burner and an open ended tube that extends within a furnace or the like and through which the hot products of combustion from the burner flow, causing the tube to radiate heat. The combustion products, after passing through the tube, are discharged outside the heated environment. Such burners find use, for example, in furnaces used for annealing strip steel.
Radiant tube burners are of the negative pressure or indirect control type in which air is drawn into the burner by suction applied at the discharge end of the radiant tube, e.g., by an eductor, or are of the positive pressure or direct control type in which forced air is introduced at the burner and pushes products of combustion through the tube.
Heat recuperation has been used with radiant tube burners (see, e.g., U.S. Pat. No. 2,700,380), but among the disadvantages of presently available systems, are the difficulty in conveniently and inexpensively applying recuperators to existing negative pressure systems, and the complexity and expense of commercially available arrangements.